During the using process of the autocontrol valve of flush toilet, the control valves using the keg float have been already used widely. This kind of valves uses the response of the keg float in the water tank to the height of water level to control the break-make of the valve, so that the water yield in the water tank of the toilet can be automatically maintained. The situation commonly seen in several modified proposals of the keg float is that the keg float is provided with a water channel, and guide holes are opened at the inlet of the whole outlet pipe, so that small amount of water expelled from the outlet pipe can pass the guide holes and drops into the water channel of the keg float, and the temporary balance weight to the keg float is present, and the stability of the promotion and demotion of the keg float is achieved by decreasing the sensitivity of the keg float.
However, there are several defects in this kind of water-storing keg float proposal with water channel: when the water pressure of the water supply is low, the amount of water flowing out of the guide holes is bare, and then it is hard to achieve the balance weight to the keg float, therefore different water pressure can cause the inconformity of stopping heights of the keg float, and the final water level is unstable.